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Kholousi Adab F, Mehdi Yaghoobi M, Gharechahi J. Enhanced crystalline cellulose degradation by a novel metagenome-derived cellulase enzyme. Sci Rep 2024; 14:8560. [PMID: 38609443 PMCID: PMC11014956 DOI: 10.1038/s41598-024-59256-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 04/08/2024] [Indexed: 04/14/2024] Open
Abstract
Metagenomics has revolutionized access to genomic information of microorganisms inhabiting the gut of herbivorous animals, circumventing the need for their isolation and cultivation. Exploring these microorganisms for novel hydrolytic enzymes becomes unattainable without utilizing metagenome sequencing. In this study, we harnessed a suite of bioinformatic analyses to discover a novel cellulase-degrading enzyme from the camel rumen metagenome. Among the protein-coding sequences containing cellulase-encoding domains, we identified and subsequently cloned and purified a promising candidate cellulase enzyme, Celcm05-2, to a state of homogeneity. The enzyme belonged to GH5 subfamily 4 and exhibited robust enzymatic activity under acidic pH conditions. It maintained hydrolytic activity under various environmental conditions, including the presence of metal ions, non-ionic surfactant Triton X-100, organic solvents, and varying temperatures. With an optimal temperature of 40 °C, Celcm05-2 showcased remarkable efficiency when deployed on crystalline cellulose (> 3.6 IU/mL), specifically Avicel, thereby positioning it as an attractive candidate for a myriad of biotechnological applications spanning biofuel production, paper and pulp processing, and textile manufacturing. Efficient biodegradation of waste paper pulp residues and the evidence of biopolishing suggested that Celcm05-2 can be used in the bioprocessing of cellulosic craft fabrics in the textile industry. Our findings suggest that the camel rumen microbiome can be mined for novel cellulase enzymes that can find potential applications across diverse biotechnological processes.
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Affiliation(s)
- Faezeh Kholousi Adab
- Department of Biotechnology, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman, Iran
| | - Mohammad Mehdi Yaghoobi
- Department of Biotechnology, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman, Iran.
| | - Javad Gharechahi
- Human Genetic Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
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Ariaeenejad S, Gharechahi J, Foroozandeh Shahraki M, Fallah Atanaki F, Han JL, Ding XZ, Hildebrand F, Bahram M, Kavousi K, Hosseini Salekdeh G. Precision enzyme discovery through targeted mining of metagenomic data. NATURAL PRODUCTS AND BIOPROSPECTING 2024; 14:7. [PMID: 38200389 PMCID: PMC10781932 DOI: 10.1007/s13659-023-00426-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/19/2023] [Indexed: 01/12/2024]
Abstract
Metagenomics has opened new avenues for exploring the genetic potential of uncultured microorganisms, which may serve as promising sources of enzymes and natural products for industrial applications. Identifying enzymes with improved catalytic properties from the vast amount of available metagenomic data poses a significant challenge that demands the development of novel computational and functional screening tools. The catalytic properties of all enzymes are primarily dictated by their structures, which are predominantly determined by their amino acid sequences. However, this aspect has not been fully considered in the enzyme bioprospecting processes. With the accumulating number of available enzyme sequences and the increasing demand for discovering novel biocatalysts, structural and functional modeling can be employed to identify potential enzymes with novel catalytic properties. Recent efforts to discover new polysaccharide-degrading enzymes from rumen metagenome data using homology-based searches and machine learning-based models have shown significant promise. Here, we will explore various computational approaches that can be employed to screen and shortlist metagenome-derived enzymes as potential biocatalyst candidates, in conjunction with the wet lab analytical methods traditionally used for enzyme characterization.
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Affiliation(s)
- Shohreh Ariaeenejad
- Department of Systems and Synthetic Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
| | - Javad Gharechahi
- Human Genetics Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Mehdi Foroozandeh Shahraki
- Laboratory of Complex Biological Systems and Bioinformatics (CBB), Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran
| | - Fereshteh Fallah Atanaki
- Laboratory of Complex Biological Systems and Bioinformatics (CBB), Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran
| | - Jian-Lin Han
- Livestock Genetics Program, International Livestock Research, Institute (ILRI), Nairobi, 00100, Kenya
- CAAS-ILRI Joint Laboratory On Livestock and Forage Genetic Resources, Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing, 100193, China
| | - Xue-Zhi Ding
- Key Laboratory of Yak Breeding Engineering, Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences (CAAS), Lanzhou, 730050, China
| | - Falk Hildebrand
- Gut Microbes and Health, Quadram Institute Bioscience, Norwich, Norfolk, UK
- Digital Biology, Earlham Institute, Norwich, Norfolk, UK
| | - Mohammad Bahram
- Department of Ecology, Swedish University of Agricultural Sciences, Ulls Väg 16, 756 51, Uppsala, Sweden
- Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, 40 Lai St, Tartu, Estonia
| | - Kaveh Kavousi
- Laboratory of Complex Biological Systems and Bioinformatics (CBB), Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran.
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Ma L, Aizhan R, Wang X, Yi Y, Shan Y, Liu B, Zhou Y, Lü X. Cloning and characterization of low-temperature adapted GH5-CBM3 endo-cellulase from Bacillus subtilis 1AJ3 and their application in the saccharification of switchgrass and coffee grounds. AMB Express 2020; 10:42. [PMID: 32140794 PMCID: PMC7058755 DOI: 10.1186/s13568-020-00975-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 02/21/2020] [Indexed: 01/27/2023] Open
Abstract
Endocellulase is a key cellulase for cellulosic material pretreatment in the industry by hydrolyzing long cellulose chains into short chains. To investigate the endocellulase characteristics from Bacillus subtilis 1AJ3, and increase its production yield, this paper cloned an endocellulase gene denoted CEL-5A from strain 1AJ3 and expressed in E. coli BL21 (DE3). The CEL-5A gene was sequenced with a full-length of 1500 bp, encoding a totally of 500 amino acids, and containing two domains: the GH5 family catalytic domain (CD) and the CBM3 family cellulose-binding domain (CBD). Recombinant endocellulase Cel-5A with a His-tag was purified of the Ni-NTA column, and SDS-PAGE results demonstrated that Cel-5A exhibited a molecular weight of 56.4 kDa. The maximum enzyme activity of Cel-5A was observed at pH 4.5 and 50 °C. Moreover, it was active over the broad temperature region of 30–60 °C, and stable within the pH range of 4.5–10.0. In addition, Co2+ was able to increase enzyme activity, while the majority of metal ions demonstrated stable enzyme activity under low- concentration. The substrate specificity of Cel-5A exhibited a high specific activity on the β-1,3-1,4 glucan linkage from barley. The Michaelis–Menten constant and the maximum velocity of the recombinant Cel-5A for CMC-Na were determined as 14.87 mg/mL and 19.19 μmol/min/mg, respectively. When Cel-5A was applied to the switchgrass and coffee grounds, its color became lighter and the biomass was observed to loosen following hydrolyzation. The saccharification rate reached 12% of the total weight of switchgrass in 20 h. These properties highlight the potential application of Cel-5A as an endocellulase in the pretreatment of biomass, for example, in the coffee grounds/waste, and related industries.
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He B, Jin S, Cao J, Mi L, Wang J. Metatranscriptomics of the Hu sheep rumen microbiome reveals novel cellulases. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:153. [PMID: 31249617 PMCID: PMC6587244 DOI: 10.1186/s13068-019-1498-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 06/14/2019] [Indexed: 05/11/2023]
Abstract
BACKGROUND Cellulosic biomass has great potential as a renewable biofuel resource. Robust, high-performance enzymes are needed to effectively utilize this valuable resource. In this study, metatranscriptomics was used to explore the carbohydrate-active enzymes (CAZymes), especially glycoside hydrolases (GHs), present in the rumen microbiome of Hu sheep. Select CAZymes were experimentally verified and characterized after cloning and expression in E. coli. RESULTS The metatranscriptomes of six Hu sheep rumen microbiomes yielded 42.3 Gbp of quality-checked sequence data that represented in total 2,380,783 unigenes after de novo assembling using Trinity and clustered with CD-HIT-EST. Annotation using the CAZy database revealed that 2.65% of the unigenes encoded GHs, which were assigned to 111 different CAZymes families. Firmicutes (18.7%) and Bacteroidetes (13.8%) were the major phyla to which the unigenes were taxonomically assigned. In total, 14,489 unigenes were annotated to 15 cellulase-containing GH families, with GH3, GH5 and GH9 being the predominant. From these putative cellulase-encoding unigenes, 4225 open reading frames (ORFs) were predicted to contain 2151 potential cellulase catalytic modules. Additionally, 147 ORFs were found to encode proteins that contain carbohydrate-binding modules (CBMs). Heterogeneous expression of 30 candidate cDNAs from the GH5 family in E. coli BL21 showed that 17 of the tested proteins had endoglucanase activity, while 7 exhibited exoglucanase activity. Interestingly, two of the GH5 proteins (Cel5A-h28 and Cel5A-h11) showed high specific activity against carboxymethylcellulose (CMC) and p-nitrophenyl-β-d-cellobioside (pNPC) (222.2 and 142.8 U/mg), respectively. The optimal pH value for activity of Cel5A-h11 and Cel5A-h28 was 6.0 for both enzymes, and optimal temperatures were 40 and 50 °C, respectively. Both enzymes retained over 70 and 60%, respectively, of their original activities after incubation at 40 °C for 60 min. However, their activities were rapidly diminished upon exposure to higher temperatures. Cel5A-h11 and Cel5A-h28 retained more than 80 and 60% of their maximal enzymatic activities after incubation for 16 h in buffered solutions in the pH range from 4.0 to 9.0. CONCLUSION The metatranscriptomic results revealed that the rumen microbiome of Hu sheep encoded a repertoire of new enzymes capable of cellulose degradation and metatranscriptomics was an effective method to discover novel cellulases for biotechnological applications.
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Affiliation(s)
- Bo He
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, 310058 China
| | - Shuwen Jin
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, 310058 China
| | - Jiawen Cao
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, 310058 China
| | - Lan Mi
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, 310058 China
| | - Jiakun Wang
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, 310058 China
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Yasir M, Qureshi AK, Khan I, Bibi F, Rehan M, Khan SB, Azhar EI. Culturomics-Based Taxonomic Diversity of Bacterial Communities in the Hot Springs of Saudi Arabia. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2018; 23:17-27. [PMID: 30589606 DOI: 10.1089/omi.2018.0176] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Hot springs are natural habitats for thermophilic microorganisms and provide a significant opportunity for bioprospecting thermostable biomolecules. However, the scientific community has only a fragmented understanding of the microbial diversity and composition in these biotopes. In this study, bacterial diversity in sediment samples from six hot springs of Saudi Arabia was investigated using an improved culture-dependent approach. High-throughput MALDI-TOF MS (matrix assisted laser desorption/ionization mass spectrometry) and 16S rRNA genes sequencing were used for the identification of purified isolates. Most of the hot springs had a neutral pH and a temperature range of 45-89°C. Relatively higher colony-forming units (1.9 ± 0.45 × 104) were observed with 60°C incubation of an 89°C sediment sample from the hot spring at Ain al Harra1. Among the 536 purified isolates, 6 novel candidate species were found, and the remaining isolates represented 139 distinct species. Several species, such as Bacillus cereus, Bacillus subtilis, and Bacillus schlegelii, were ubiquitous in the hot springs sampled, but 102 of the identified species were uniquely distributed among the hot springs. Sixteen of the isolated thermophilic bacteria, including Geobacillus kaustophilus, Thermus oshimai, and Brevibacillus thermoruber, grew at ≥60°C. In addition, 21 species exhibited hydrolytic enzymatic activity. Most of these species belonged to Bacillus and Brevibacillus. Overall, this study contributes to global knowledgebase on bacterial communities by comprehensively profiling culture-based bacterial diversity in the hot springs of Saudi Arabia. Further studies are required for investigating bacteria from hot springs by a metagenomic approach.
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Affiliation(s)
- Muhammad Yasir
- 1 Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Arooj K Qureshi
- 1 Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Imran Khan
- 1 Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.,2 State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology Taipa, Macau, China
| | - Fehmida Bibi
- 1 Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mohd Rehan
- 3 King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Sher Bahadar Khan
- 4 Department of Chemistry, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Esam I Azhar
- 1 Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.,5 Medical Laboratory Technology Department, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
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Escuder-Rodríguez JJ, DeCastro ME, Cerdán ME, Rodríguez-Belmonte E, Becerra M, González-Siso MI. Cellulases from Thermophiles Found by Metagenomics. Microorganisms 2018; 6:microorganisms6030066. [PMID: 29996513 PMCID: PMC6165527 DOI: 10.3390/microorganisms6030066] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 07/04/2018] [Accepted: 07/05/2018] [Indexed: 01/05/2023] Open
Abstract
Cellulases are a heterogeneous group of enzymes that synergistically catalyze the hydrolysis of cellulose, the major component of plant biomass. Such reaction has biotechnological applications in a broad spectrum of industries, where they can provide a more sustainable model of production. As a prerequisite for their implementation, these enzymes need to be able to operate in the conditions the industrial process requires. Thus, cellulases retrieved from extremophiles, and more specifically those of thermophiles, are likely to be more appropriate for industrial needs in which high temperatures are involved. Metagenomics, the study of genes and gene products from the whole community genomic DNA present in an environmental sample, is a powerful tool for bioprospecting in search of novel enzymes. In this review, we describe the cellulolytic systems, we summarize their biotechnological applications, and we discuss the strategies adopted in the field of metagenomics for the discovery of new cellulases, focusing on those of thermophilic microorganisms.
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Affiliation(s)
- Juan-José Escuder-Rodríguez
- Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Bioloxía, Facultade de Ciencias, Universidade da Coruña, 15071 A Corunna, Spain.
| | - María-Eugenia DeCastro
- Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Bioloxía, Facultade de Ciencias, Universidade da Coruña, 15071 A Corunna, Spain.
| | - María-Esperanza Cerdán
- Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Bioloxía, Facultade de Ciencias, Universidade da Coruña, 15071 A Corunna, Spain.
| | - Esther Rodríguez-Belmonte
- Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Bioloxía, Facultade de Ciencias, Universidade da Coruña, 15071 A Corunna, Spain.
| | - Manuel Becerra
- Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Bioloxía, Facultade de Ciencias, Universidade da Coruña, 15071 A Corunna, Spain.
| | - María-Isabel González-Siso
- Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Bioloxía, Facultade de Ciencias, Universidade da Coruña, 15071 A Corunna, Spain.
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Gupta P, Mishra AK, Vakhlu J. Cloning and characterization of thermo-alkalistable and surfactant stable endoglucanase from Puga hot spring metagenome of Ladakh (J&K). Int J Biol Macromol 2017; 103:870-877. [DOI: 10.1016/j.ijbiomac.2017.05.113] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/16/2017] [Accepted: 05/18/2017] [Indexed: 11/28/2022]
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Bai X, Yuan X, Wen A, Li J, Bai Y, Shao T. Cloning, expression and characterization of a cold-adapted endo-1, 4- β-glucanase from Citrobacter farmeri A1, a symbiotic bacterium of Reticulitermes labralis. PeerJ 2016; 4:e2679. [PMID: 27843715 PMCID: PMC5103814 DOI: 10.7717/peerj.2679] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 10/12/2016] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Many biotechnological and industrial applications can benefit from cold-adapted EglCs through increased efficiency of catalytic processes at low temperature. In our previous study, Citrobacter farmeri A1 which was isolated from a wood-inhabiting termite Reticulitermes labralis could secrete a cold-adapted EglC. However, its EglC was difficult to purify for enzymatic properties detection because of its low activity (0.8 U/ml). The objective of the present study was to clone and express the C. farmeri EglC gene in Escherichia coli to improve production level and determine the enzymatic properties of the recombinant enzyme. METHODS The EglC gene was cloned from C. farmeri A1 by thermal asymmetric interlaced PCR. EglC was transformed into vector pET22b and functionally expressed in E. coli. The recombination protein EglC22b was purified for properties detection. RESULTS SDS-PAGE revealed that the molecular mass of the recombinant endoglucanase was approximately 42 kDa. The activity of the E. coli pET22b-EglC crude extract was 9.5 U/ml. Additionally, it was active at pH 6.5-8.0 with an optimum pH of 7.0. The recombinant enzyme had an optimal temperature of 30-40 °C and exhibited >50% relative activity even at 5 °C, whereas it lost approximately 90% of its activity after incubation at 60 °C for 30 min. Its activity was enhanced by Co2+ and Fe3+, but inhibited by Cd2+, Zn2+, Li+, Triton X-100, DMSO, acetonitrile, Tween 80, SDS, and EDTA. CONCLUSION These biochemical properties indicate that the recombinant enzyme is a cold-adapted endoglucanase that can be used for various industrial applications.
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Affiliation(s)
- Xi Bai
- Institute of Ensiling and Processing of Grass, Nanjing Agricultural University , Nanjing , China
| | - Xianjun Yuan
- Institute of Ensiling and Processing of Grass, Nanjing Agricultural University , Nanjing , China
| | - Aiyou Wen
- College of Animal Science, University of Science and Technology of Anhui , Fengyang , China
| | - Junfeng Li
- Institute of Ensiling and Processing of Grass, Nanjing Agricultural University , Nanjing , China
| | - Yunfeng Bai
- Institute of Agricultural Resource and Environment, Jiangsu Academy of Agricultural Sciences , Nanjing , China
| | - Tao Shao
- Institute of Ensiling and Processing of Grass, Nanjing Agricultural University , Nanjing , China
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Loc NH, Ngoc LMT, Quang HT, Huy ND, Luong NN. Cloning and expression of two genes coding endo-β-1,4-glucanases from Trichoderma asperellum PQ34 in Pichia pastoris. CHEMICAL PAPERS 2016. [DOI: 10.1515/chempap-2015-0210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractTwo genes coding endo-β-1,4-glucanases were cloned from Trichoderma asperellum PQ34 which was isolated from Thua Thien Hue province, Vietnam. The expression of these genes in Pichia pastoris produced two enzymes with molecular masses of approximately 46 kDa (about 42 kDa of enzymes and 4 kDa of signal peptide). The effects of induction time and temperature, inducer concentration, and culture medium on the endo-β-1,4-glucanase activity were investigated. The results showed that the highest total activities of two endo-β-1,4-glucanases were approximately 4.7 × 10
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Montella S, Amore A, Faraco V. Metagenomics for the development of new biocatalysts to advance lignocellulose saccharification for bioeconomic development. Crit Rev Biotechnol 2015; 36:998-1009. [PMID: 26381035 DOI: 10.3109/07388551.2015.1083939] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The world economy is moving toward the use of renewable and nonedible lignocellulosic biomasses as substitutes for fossil sources in order to decrease the environmental impact of manufacturing processes and overcome the conflict with food production. Enzymatic hydrolysis of the feedstock is a key technology for bio-based chemical production, and the identification of novel, less expensive and more efficient biocatalysts is one of the main challenges. As the genomic era has shown that only a few microorganisms can be cultured under standard laboratory conditions, the extraction and analysis of genetic material directly from environmental samples, termed metagenomics, is a promising way to overcome this bottleneck. Two screening methodologies can be used on metagenomic material: the function-driven approach of expression libraries and sequence-driven analysis based on gene homology. Both techniques have been shown to be useful for the discovery of novel biocatalysts for lignocellulose conversion, and they enabled identification of several (hemi)cellulases and accessory enzymes involved in (hemi)cellulose hydrolysis. This review summarizes the latest progress in metagenomics aimed at discovering new enzymes for lignocellulose saccharification.
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Affiliation(s)
- Salvatore Montella
- a Department of Chemical Sciences , University of Naples "Federico II", Complesso Universitario Monte S. Angelo , Naples , Italy
| | - Antonella Amore
- a Department of Chemical Sciences , University of Naples "Federico II", Complesso Universitario Monte S. Angelo , Naples , Italy
| | - Vincenza Faraco
- a Department of Chemical Sciences , University of Naples "Federico II", Complesso Universitario Monte S. Angelo , Naples , Italy
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Telke AA, Zhuang N, Ghatge SS, Lee SH, Ali Shah A, Khan H, Um Y, Shin HD, Chung YR, Lee KH, Kim SW. Engineering of family-5 glycoside hydrolase (Cel5A) from an uncultured bacterium for efficient hydrolysis of cellulosic substrates. PLoS One 2013; 8:e65727. [PMID: 23785445 PMCID: PMC3681849 DOI: 10.1371/journal.pone.0065727] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 04/27/2013] [Indexed: 01/29/2023] Open
Abstract
Cel5A, an endoglucanase, was derived from the metagenomic library of vermicompost. The deduced amino acid sequence of Cel5A shows high sequence homology with family-5 glycoside hydrolases, which contain a single catalytic domain but no distinct cellulose-binding domain. Random mutagenesis and cellulose-binding module (CBM) fusion approaches were successfully applied to obtain properties required for cellulose hydrolysis. After two rounds of error-prone PCR and screening of 3,000 mutants, amino acid substitutions were identified at various positions in thermotolerant mutants. The most heat-tolerant mutant, Cel5A_2R2, showed a 7-fold increase in thermostability. To enhance the affinity and hydrolytic activity of Cel5A on cellulose substrates, the family-6 CBM from Saccharophagus degradans was fused to the C-terminus of the Cel5A_2R2 mutant using overlap PCR. The Cel5A_2R2-CBM6 fusion protein showed 7-fold higher activity than the native Cel5A on Avicel and filter paper. Cellobiose was a major product obtained from the hydrolysis of cellulosic substrates by the fusion enzyme, which was identified by using thin layer chromatography analysis.
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Affiliation(s)
- Amar A. Telke
- Division of Applied Life Sciences (BK21), PMBBRC, Gyeongsang National University, Jinju, Republic of Korea
| | - Ningning Zhuang
- Division of Applied Life Sciences (BK21), PMBBRC, Gyeongsang National University, Jinju, Republic of Korea
| | - Sunil S. Ghatge
- Division of Applied Life Sciences (BK21), PMBBRC, Gyeongsang National University, Jinju, Republic of Korea
| | - Sook-Hee Lee
- Division of Applied Life Sciences (BK21), PMBBRC, Gyeongsang National University, Jinju, Republic of Korea
| | - Asad Ali Shah
- Division of Applied Life Sciences (BK21), PMBBRC, Gyeongsang National University, Jinju, Republic of Korea
| | - Haji Khan
- Division of Applied Life Sciences (BK21), PMBBRC, Gyeongsang National University, Jinju, Republic of Korea
| | - Youngsoon Um
- Center for Environmental Technology Research, KIST, Seoul, Republic of Korea
| | - Hyun-Dong Shin
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Young Ryun Chung
- Division of Applied Life Sciences (BK21), PMBBRC, Gyeongsang National University, Jinju, Republic of Korea
| | - Kon Ho Lee
- Division of Applied Life Sciences (BK21), PMBBRC, Gyeongsang National University, Jinju, Republic of Korea
- Department of Microbiology, School of Medicine, Gyeongsang National University, Jinju, Republic of Korea
- * E-mail: (SWK); (KHL)
| | - Seon-Won Kim
- Division of Applied Life Sciences (BK21), PMBBRC, Gyeongsang National University, Jinju, Republic of Korea
- * E-mail: (SWK); (KHL)
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